Here's another film to file in my storyline category of "The Rebel vs The Rulebook." But it goes well past this premise to offer a tremendously enjoyable outing, complete with great music.

Deloris Van Cartier (Whoopi Goldberg) is the big-haired lead singer of The Ronelles, a trio that performs Motown and other early 1960s classics in the Moonlight Lounge of the Nevada Club in Reno. She is also the girlfriend of married casino owner Vince LaRocca (Harvey Keitel), who, unbeknownst to her, has ties to organized crime. After she witnesses one of his killings, she runs to the police to report the crime. Lt. Eddie Souther (Bill Nunn) vows to put Deloris into protective custody so she'll be able to testify against Vince in court. "I'm going to put you in the last place on Earth that Vince would ever look for you," Eddie says -- which turns out to be a Catholic church and convent in San Francisco, more than 200 miles away.

At St. Katherine's Parish, Deloris is transformed into Sister Mary Clarence, complete with full habit. She and the stern Reverend Mother (Maggie Smith) clash at nearly every turn, as should be expected. But she gets to know and to befriend some of the women, including young novitiate Mary Robert (Wendy Makkena) and the effervescent Sister Mary Patrick (Kathy Najimy). When it seems to Mother Superior that Mary Clarence is leading these sisters astray, she assigns her a new and daunting task: to participate in the convent choir.

The choir is awful. Simply awful. Painful to hear. Choir mistress Sister Mary Lazarus (Mary Wickes) has seemingly done her best with the group, but they remain as unmusical as is conceivably possible. Mary Clarence gives them some beginning advice; and before you know it, the nuns are singing in tune and with feeling. And much to the Reverend Mother's chagrin, they quickly gain the support of Monsignor O'Hara (Joseph Maher), the parish priest.

Mary Clarence influences not just the choir, but also the sisters' involvement in their community. And as the church and convent begin to succeed, they also begin to attract media publicity. How much longer can Deloris get away with hiding at St. Katherine's before Vince and his two thugs, Joey (Robert Miranda) and Willy (Richard Portnow), find her to silence her? Can she at least stay with her new friends to get ready for their biggest performance ever?

The script is somewhat but not entirely predictable. Everyone is perfectly believable in their roles. It's difficult to imagine any other actors portraying any of the characters. In real life, the church is St. Paul's Catholic Church in San Francisco, and its neighborhood is not at all as downtrodden as is depicted here, fortunately. The streetscapes were altered for filming purposes. The real-life Nevada Club operated in Reno from the 1940s until 1997. The building was demolished in 1999.

The star of this show is its terrific and contagious soundtrack. Who knew that soul songs from the early 1960s could be transformed into liturgical music? I am not Catholic and am not even a fan of organized religious programs. But after I saw Sister Act for the first time, "Salve Regina" became one of my favorites. It stays in my head for days after watching this film. For many days after. Which is not necessarily a bad thing.

From the multiple meanings of the movie title, to the simple story and its gratifying conclusion, Sister Act is a pure delight. If you haven't watched it lately, then it's time to tune into it again. Literally. Sing along, if you wish. It is followed by Sister Act 2: Back in the Habit.